Sound recording and reproducing apparatus



Aug. 18, 1964 w. s. PAJES 3,145,267

SOUND RECORDING AND REPRODUCING APPARATUS Filed March 28. 1958 6 f D, POWER AMPLIFIER J P5: g/l'z 7 7 swasp (IRCUIT 2 i If h M /6 I Z6 33 H 2 AMPLIFIER INVENTOR.

WOLF SZMUL PAJ'ES ATTORNEY United States Patent 3,145,257 SOUND RECGRDING AND REPRODUCING APPARATUS Wolf Szmul Pajes, 316 West End Ave., New York 23, NY. Filed Mar. 28, 1958, Ser. No. 724,572 Claims. (Cl. 179-1002) an immediate playback and thus hear the quality of their pronunciation, the advantage being that enunciation corrections can be easily made by proper fashioning of the organs of speech. The apparatus produces an effect like an echo, and is thus the counterpart of a mirror in the realm of sound. The echo effect comes into being only after pressing a control button. Because the button can be pressed at any time, even after a single word has been recorded, corrections of enunciation can be made within an interval of time when the memory of the manner of pronunciation is still fresh.

A person never knows how his speech sounds unless he actually hears it reproduced. It is therefore important to correct enunciation by fashioning the speech organs while the manner of prior efforts of speech organ fashioning is still remembered.

The invention is illustrated in the drawings, in which:

FIGURE 1 is a schematic representation of a preferred form of apparatus using a cathode ray tube for the recording and reproducing; and

FIGURE 2 is an enlarged view of a portion of the memory device.

In the particular form of the invention shown, the recording is accomplished by a memory device which comprises a thin sheet of magnetic material. A modulated beam of electrons is projected through the sheet and the beam is caused to scan the sheet in a predetermined path, whereby, in effect, discrete portions of said sheet in the scanning sequence become magnetized because of the circular magnetic fields produced by the beam (Biot-Savart effect), as shown in FIGURE 2. The process of reproduction is then accomplished by rescanning the sheet with an unmodulated beam along the same path and utilizing the variations of intensity produced in the beam when it passes through the sheet.

In the figure, a cathode ray tube 1 is shown having an electron gun 2, a control electrode 3, and an anode or plate 4. A voltage divider 5 is connected across a direct current power supply 6 which may be connected over a switch 6' to a source of alternating current which may be the house lighting circuit. The voltage divider 5 provides a source of different direct current potentials for the several electrodes of the cathode ray tube in a known manner to cause a beam of electrons 7 to be projected from the gun 2, through the control electrode 3, to the anode 4. A sweep circuit 8 is provided to cause the electron beam to sweep across the anode, as, for instance, in the usual series of parallel horizontal lines, but at a relatively slow rate, as will be explained.

Adjacent the anode in the path of the electron beam I provide a sheet 9 of extremely thin magnetizable material, such as iron oxide (Fe O supported in a frame 10, and I adjust the voltage between the cathode and anode so that the electron beam will pass through the sheet 9, similar to the passage of electrons through a Lenard window.

When a beam of electrons passes through the mag! netizable sheet 9, a circular magnetic field 9' is set up in a small portion of the sheet around the path of the beam, as shown in FIGURE 2, so that this portion of the sheet is magnetized, the magnetization beingproportional to the intensity of the beam. Of course the magnetic field produced by the beam extends indefinitely from the beam. Significant intensities, however, are to be found in the immediate neighborhood of the beam. If the modulated beam is caused to sweep across the sheet, it will leave behind it a modulated magnetized path mirroring the variation in intensity of the beam.

After the sheet, or a portion of it, has been thus magnetized, if the unmodulated beam is again caused to sweep across the sheet in the same path, the beam will be modulated by the varying amounts of magnetization of the sheet portions, so that the anode current will now be modulated in accordance with the information applied to the sheet at the first sweep of the beam. Thus, information may be recorded on the sheet at one sweep of the electron beam and read 01f at the next sweep of the beam.

Some means must be provided to remove therecorded information from the sheet to prepare it for the next recording. This may be accomplished by a magnetic fieldset up by a decaying alternating current. One manner of producing such a field is illustrated in FIGURE 1. A coil 11 is placed around the cathode ray tube 1 in the plane of the sheet 9, and is provided with a pulse of alternating current in a manner to be explained which starts at a predetermined amplitude and decays to zero during a certain increment of time.

A transducer 12 is used, first as a microphone to translate sound variations into electrical variations to modulate the electron beam, and then as a lound speaker to translate the electrical variations from the anode of the cathode ray tube into sound variations. in each case are amplified by an amplifier 13 in a manner to be described.

In order to control the recording and reproducing apparatus, I use a single multi-contact, two-position control switch 14 which, in its normal or first position, makes the necessary connections for recording the sound, and in its other or second position makes all the connections for reproducing the recorded sound. I preferably use a springcontrolled switch, for example, with resilient blades in which the resiliency of the blades will maintain the switch in its normal or first position, and pressure on a suitable knob or button will shift it to its second position, while removal of the pressure will cause the switch to return to its normal position again.

The blades 15 and 16 control the current through the coil 11 for erasing the sound previously recorded, and each blade has a break contact and a make contact. A condenser 17 is connected between the two blades 15 and 16 and a portion of the voltage divider 5 is connected by means of leads 18 and 18' between the break contacts, so that with the switch in its normal position, as shown, the condenser will be charged by current from the, voltage divider 5.

In order to supply the coil 11 with alternating current and control the current by means of the charge on the condenser, I provide a transformer 19 having a primary winding 20 which is connected to the source of the alternating current so as to be controlled by the switch 6'. The transformer 19 has a secondary winding 21 the ends.

tion, or so as to oppose each other. The center point 24 of the secondary winding 21 is connected to the makecontact of the switch blade 15, while the coil 11 has a center The electrical variations 7 3 tap 25 which is connected to the make contact of the switch blade 16.

When the switch is operated, the blades and 16 connect the condenser 17 between the center point 24 of the secondary winding 21 and the center tap of the coil 11. The poling of the connections 18 and 18' and the rectifiers 22 and 23 is such that when the switch is operated, the condenser will discharge through the halves of the coil 11 and the halves of the secondary winding 21 and through the rectifiers 22 and 23, half the current passing through one rectifier and the other half passing through the other rectifier. As long as the direct current from the condenser passes through the rectifiers, alternating current will flow through the coil 11, but when the direct current ceases, the rectifiers block the alternating current. Since the charge on the condenser quickly decays, alterhating current in the coil 11 will also decay quickly and the decaying electromagnetic field will demagnetize the sheet 9.

The operation of the switch also controls the operation of the sweep circuit 8. To this end a blade 26 of the Switch has a break contact and a make contact. Both contacts are connected together and to one lead 27 of the control circuit for the sweep circuit. The other lead 28 of the control circuit is connected to the switch blade 26. Normally the break contact closes the control circuit by connecting the leads 27 and 28 which causes the sweep circuit to operate. Thus the electron beam is normally sweeping across the sheet 9. However, the act of operating the switch first causes the break contact to open, which stops the sweep, and then, with a further movement of the switch, the make contact closes and connects the wires 27 and 28 together again. This starts the sweep circuit again, the arrangement being such that the beam will start at the beginning of its sweep.

The switch also controls the connections for the amplifier 13 and the transducer 12. A blade 29 of the switch is connected through a coupling condenser 30 to the control grid 3 of the cathode ray tube 1 and has a make contact connected to the output 31 of the amplifier 13. A blade 32 is connected to one terminal of the coil of the transducer 12, the other terminal of the coil being grounded. This blade 32 has a break contact connected to the output 31 of the amplifier 13, so that when the switch is unoperated, the transducer is connected to the output of the amplifier. It also has a make contact connected to the input 33 of the amplifier. The switch also has a blade 34 which is connected through a condenser 35 to the anode 4 of the cathode ray tube 1, and a break contact connected to the input 33 of the amplifier 13, so that when the switch is unoperated, the anode 4 of the cathode ray tube is connected to the input of the amplifier, and when the switch is operated, the anode is unconnected, except to its source of operating potential.

In using the apparatus, it is assumed that the power has been turned on by means of the switch 6. The switch 14 is in its normal position with the sweep circuit 8 operating and the condenser 17 charged. The operator now desires to speak one word or a number of words in a sentence or series of sentences into the transducer and depresses the switch 14, holding it in its operated position. As he depresses the switch, the first thing that happens is that the sweep of the electron beam is caused to stop as the switch blade 26 leaves its break contact. When the blades 15 and 16 reach their make contacts, the condenser 17 is connected between the center point 24 of the transformer secondary 21 and the center tap 25 of the coil 11. This permits alternating current to flow briefly through the coil 11, and as the flow of current decays, the sheet 9 is demagnetized. The switch is preferably arranged so that the blades 15 and 16 reach their make contacts before the blade 26 reaches its make contact. When this occurs, however, the electron beam commences its sweep across the sheet 9. Meanwhile the blades 29 and 32 have connected the amplifier 13 in circuit between the transducer i 12 and the control grid 3 of the cathode ray tube, with the transducer connected to the input of the amplifier and the output of the amplifier connected to the control grid 3.

All this happens in a fraction of a second. The operator now speaks into the transducer 12, still holding the switch depressed. The modulations of his voice are translated into electrical variations which are amplified and applied to the control grid 3 where they in turn modulate the electron beam. As the modulated beam passes through the sheet 9, it magnetizes discrete portions of the sheet, as explained above.

The operator may speak one word or a number of sentences, as he desires. When he has finished speaking, he releases the switch 14. At the switch blade 26, the opening of the make contact stops the sweep circuit 8, whereby the beam returns to its normal position, and when the break contact closes, the beam starts its sweep again, tracing over the same path in which the recording had previously been made. At the switch blade 32, the closing of the break contact connects the transducer 12 to the output of the amplifier 13, and at the switch blade 34, the closure of the break contact connects the anode of the cathode ray tube to the input of the amplifier. The electron beam is now modulated by the magnetized portions of the sheet 9 and modulates the potential of the anode which in turn operates the transducer 12, and the operator hears the sounds he has previously recorded.

The return of the switch blades 15 and 16 to their break contacts connects the condenser 17 again across the source of potential, so that the condenser charges again in readiness to remove the recorded information from the sheet 9 the next time the switch 14 is depressed.

Since the apparatus is used for sound recording, the speed of the cathode ray beam as it sweeps across the sheet 9 should correspond to the speed of a magnetic tape through a tape recording apparatus. It is evident, however, that the speed can be made very much faster so that it is possible to record and reproduce the sound with great fidelity. Of course the sweep may be made to assume any desired pattern, as, for example, a spiral.

Various modifications may be made in the apparatus shown and described without departing from the spirit of the invention, and I do not therefore wish to limit the invention except by the limitations contained in the appended claims.

What I desire to claim and secure by Letters Patent is:

1. A memory device comprising a thin sheet of magnetizable material, means for producing a beam of electrons having sufiicient velocity to pass through said sheet, an anode on the other side of said sheet from said beamproducing means for receiving electrons which have passed through said sheet, means for modulating said beam of electrons in accordance with information to be recorded, means for causing said beam of electrons to scan a predetermined path across said sheet, whereby a continuous succession of portions of said sheet are magnetized, and means for translating electrical variations produced on said anode when an unmodulated beam of electrons is modulated by the magnetized portions of said sheet as said beam passes through it.

2. A recording and reproducing apparatus comprising a memory device, means for recording a sequence of electrical variations in said memory device, means for reading said sequence of electrical variations from said memory device, means for operating said recording and reading means alternatively at any time, and means for causing said recording and reading means, when operated, to start at the same predetermined point of said memory device, said memory device comprising a sheet of magnetizable material thin enough to be permeable by beam of electrons, said recording means comprising means for generating a beam of electrons, means for directing it through said sheet, means for causing it to scan a predetermined path on said sheet, and means for modulating it, and said reading means including said beam generating means and said beam scanning means and further comprising an anode adapted to receive electrons from said beam after they have passed through said sheet.

3. A recording and reproducing apparatus, as defined in claim 2, further comprising means controlled by the operating means for removing electrical variations previously recorded in the memory device.

4. A recording and reproducing apparatus comprising a memory device, means for recording a sequence of electrical variations in said memory device, means for reading said sequence of variations from said memory device, a transducer, means for causing said transducer to control said recording means so as to record a sequence of electrical variations produced by said transducer, means for causing said reading means to control said transducer to translate a sequence of electrical variations produced by said reading means, means for operating one of said control means immediately after said other control means has completed its controlling action, and means operated by said last-mentioned means for removing electrical vari ations stored in said memory device, said memory device comprising a sheet of magnetizable material thin enough to be permeable by a beam of electrons, said recording means comprising means for generating a beam of electrons, means for directing it through said sheet, means for causing it to scan a predetermined path on said sheet, and means for modulating it, and said reading means including said beam generating means and said beam scanning means and further comprising an anode adapted to receive electrons from said beam after they have passed through said sheet.

5. A recording and reproducing apparatus, as defined in claim 4, in which the operating means comprises a single, two-position, multi-contact switch, means including contacts of said switch when in a first position for connecting the transducer to the anode, and contacts of said switch when in the second position for connecting said transducer to the beam-modulating means, and in which the means for removing electrical variations stored in the memory device comprises a source of alternating current, a coil surrounding the magnetizable sheet and means controlled by the contacts of said switch and connected between said source and said coil for producing a surge of alternating current in said coil when said switch is placed in its second position which starts at a maximum and decays to zero immediately after said switch is moved to its second position.

References Cited in the file of this patent V UNITED STATES PATENTS 2,468,782 Ross et a1. May 3, 1949 2,591,842 Llewellyn Apr. 8, 1952 2,645,712 Rajchman et a1. July 14, 1953 2,657,377 Gray Oct. 27, 1953 2,657,378 Gray Oct. 27, 1953 2,698,928 Pulvari Jan. 4, 1955 2,706,246 Klemperer Apr. 12, 1955 2,719,884 Reed et a1. Oct. 4, 1955 2,989,594 McKaig June 20, 1961 3,007,078 Luftman et a1. Oct. 31, 1961 FOREIGN PATENTS 770,127 Great Britain Mar. 13, 1957 

4. A RECORDING AND REPRODUCING APPARATUS COMPRISING A MEMORY DEVICE, MEANS FOR RECORDING A SEQUENCE OF ELECTRICAL VARIATIONS IN SAID MEMORY DEVICE, MEANS FOR READING SAID SEQUENCE OF VARIATIONS FROM SAID MEMORY DEVICE, A TRANSDUCER, MEANS FOR CAUSING SAID TRANSDUCER TO CONTROL SAID RECORDING MEANS SO AS TO RECORD A SEQUENCE OF ELECTRICAL VARIATIONS PRODUCED BY SAID TRANSDUCER, MEANS FOR CAUSING SAID READING MEANS TO CONTROL SAID TRANSDUCER TO TRANSLATE A SEQUENCE OF ELECTRICAL VARIATIONS PRODUCED BY SAID READING MEANS, MEANS FOR OPERATING ONE OF SAID CONTROL MEANS IMMEDIATELY AFTER SAID OTHER CONTROL MEANS HAS COMPLETED ITS CONTROLLING ACTION, AND MEANS OPERATED BY SAID LAST-MENTIONED MEANS FOR REMOVING ELECTRICAL VARIATIONS STORED IN SAID MEMORY DEVICE, SAID MEMORY DEVICE COMPRISING A SHEET OF MAGNETIZABLE MATERIAL THIN ENOUGH TO BE PERMEABLE BY A BEAM OF ELECTRONS, SAID RECORDING MEANS COMPRISING MEANS FOR GENERATING A BEAM OF ELECTRONS, MEANS FOR DIRECTING IT THROUGH SAID SHEET, MEANS FOR CAUSING IT TO SCAN A PREDETERMINED PATH ON SAID SHEET, AND MEANS FOR MODULATING IT, AND SAID READING MEANS INCLUDING SAID BEAM GENERATING MEANS AND SAID BEAM SCANNING MEANS AND FURTHER COMPRISING AN ANODE ADAPTED TO RECEIVE ELECTRONS FROM SAID BEAM AFTER THEY HAVE PASSED THROUGH SAID SHEET. 